Biomedical subjects
A Nilsen
Publications and source records attributed to A Nilsen.
Investigating the effect of clustering of the urban field on sustainable population growth of centrally located and peripheral towns.
In a previous study (Portnov and Erell, 1998a), an Index of Clustering was defined, which allowed an analysis of the combined effect of spatial isolation and remoteness of peripheral towns on the long-term patterns of their population growth. In the present paper, the analysis of the effect of clustering of the urban field on the patterns of population growth is extended to centrally located urban places, and the validity of this index is tested in two unevenly populated countries--Israel and Norway. In both countries, the effect of clustering of the urban field on the patterns of urban growth is twofold. In sparsely populated areas, the presence of neighboring towns appears to increase their chances of attracting potential migrants due to inter-urban exchanges, while in more densely populated areas, increasing clustering tends to reduce migration influx to a given locality due to inter-town competition. Following this conclusion, a strategy of "redirecting priorities" leading to the formation of urban clusters is proposed, which may enhance the potential of urban growth in geographical areas where this is desirable.
Papillomavirus infection among abortion applicants and patients at a sexually transmitted disease clinic.
The base-line prevalence of human papillomavirus (HPV) infection among applicants for first trimester induced abortion and among a sexually transmitted disease (STD) clinic population with macroscopically visible condyloma is investigated. Cervical cells were collected from 505 women applying for induced abortion. Cell scrapes were obtained from the surface of the warts from 81 female and 32 male STD patients. HPV DNA 6/11, 16/18, and 31/33/35 were detected by a dot blot technique (ViraPap and ViraType, Life Technologies, Gaithersburg, MD). Of the 505 abortion applicants, 31 (6.1%) had HPV DNA. In the STD population, 64 (79.0%) patients had positive test results for HPV DNA from cervical, introital cell scrapes, or both. Of the 32 male STD patients from whom preputial, urethral samples, or both were taken, 24 (75%) had HPV DNA. After typing, the relative proportion of HPV 6/11 was 9.7% in abortion applicants, 72.2% in female STD patients, and 91.3% in male STD patients. The relative proportion of high-risk HPV types, such as 16/18 and 31/33/35, was 89.7% among abortion applicants, 38.9% among female STD patients and 13.0% among male STD patients. The majority of abortion applicants infected with HPV were thus infected with a potentially oncogenic HPV type, and the prevalence of HPV type 16/18 and 31/33/35 was also high among female STD patients.